Abstract
Copper Damascene via bottom accelerating additives was investigated by patterned cathode of cathode only at trench bottom. The cathodic current on a patterned trench bottom cathode increases with SPS in addition to Cl-, PEG and JGB. This current also increases with increase of SPS concentration. This accelerating effect of SPS has been found with typical combination of four additives (Cl-+PEG+JGB+SPS) used for via filling. The cathodic current increases with increase of aspect ratio of patterned cathode. With higher aspect ratio of deeper trench, the trench bottom accelerating substance is considered to accumulated at trench bottom. This substance is related to SPS. From the cross section observation of deposit thickness, this trench bottom accelerating substance is considered to be formed during electrolysis. This accumulates at trench of deeper trench during electrolysis. SPS decomposes into monomer by electrolysis and this may accumulates at trench bottom and increases the trench bottom current.
